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J Dørup

Publications and source records attributed to J Dørup.

11 recordsLinked to original sources
PubMed1992

Blood glucose and insulin responses to different meals in non-insulin-dependent diabetic subjects of both sexes.

The influence of sex on glucose and insulin responses in patients with non-insulin-dependent diabetes was studied in 12 men and 11 matched women. Two meals of either 100 g white bread or 60 g (raw weight) white rice were given. Blood glucose response areas to white bread (517 vs 509 mmol/L) and to rice (306 vs 353 mmol/L) over a 300-min observation period were similar in females and males, respectively. Insulin responses showed an identical pattern to that of glucose in females and males--35784 vs 28230 pmol/L after white bread and 28044 vs 19464 pmol/L min after rice (NS) over a 300-min observation period, respectively. Within the two study groups, blood glucose-response areas to white bread were significantly higher than those to rice (P less than 0.05), whereas there were no differences in insulin-response areas within or between the two groups. The glycemic index of rice for females (62 +/- 9; mean +/- SE) and males (66 +/- 5) was similar.

Blood Glucose↗
PubMed1992

Day-to-day variation of blood glucose and insulin responses in NIDDM subjects after starch-rich meal.

OBJECTIVE: To study day-to-day variation of postprandial blood glucose and insulin increments in non-insulin-dependent diabetes mellitus (NIDDM) subjects and to analyze intra- and interperson variance of response. RESEARCH DESIGN AND METHODS: Ten NIDDM subjects attending the outpatient clinic at Aarhus Kommunehospital were studied. The subjects ate three meals of 90 g of white bread, with 7 days between tests. RESULTS: Mean +/- SD areas under the blood glucose response curve (above basal) over a 3-h period were 557 +/- 60, 569 +/- 74, and 565 +/- 67 mM x 180 min (NS), and areas under the insulin-response curve were 3350 +/- 448, 2815 +/- 359 and 3551 +/- 679 mU/L x 180 min (NS) on each of the three occasions. The 95% confidence intervals of blood glucose and insulin areas for the test meal repeated three times were 564 +/- 120 mM x 180 min and 3240 +/- 1645 mU/L x 180 min, respectively. Intra- and interperson components of variance were 25 vs. 75% (glucose) and 78 vs. 22% (insulin) of the total variance. The intraperson components of variance included all sources of variation other than between-person variation. There was no significant correlation between blood glucose and insulin response areas. CONCLUSIONS: A valid estimate of the glycemic response in a single patient is obtained after a single meal. Because of the large between-person variation, paired data should preferably be used when comparing glycemic responses to different foods.

Blood Glucose↗
PubMed1992

Tubule-tubule and tubule-arteriole contacts in rat kidney distal nephrons. A morphologic study based on computer-assisted three-dimensional reconstructions.

BACKGROUND: Functional investigations of the tubulo-glomerular feedback mechanism have indicated the existence of a contact between the distal nephron and the macula densa region. The structural justification of such a contact is investigated. EXPERIMENTAL DESIGN: Tubule-tubule and tubule-arteriole contacts were investigated in distal nephrons from normal rat kidneys. Computer-assisted three-dimensional reconstructions of distal nephrons were made from serial sections of renal cortical tissue and selected sections were examined by electron microscopy. RESULTS: In 14 of 15 reconstructed nephrons, the distal convoluted tubule or the connecting tubule approached the macula densa region. A wall-to-wall contact between two tubules corresponding to a three-dimensional distance below 28 microns between the axes of the two tubules was found in only five of the reconstructed tubules. The distal nephron contacts to afferent and efferent arterioles of the same nephron were also examined. The efferent arteriole revealed no consistent contacts but the afferent arteriole contacted the distal convoluted tubule/connecting tubules consistently in all 10 of the superficial nephrons and in 3 of 5 midcortical nephrons. Electron microscopy confirmed a close contact between the distal tubule and the afferent arteriole in superficial nephrons and small nerves were often found at or near the site of contact, but the morphology at the site of contact was not unique. The arteriole contacts were made with late distal convoluted tubules, connecting tubules, or cortical collecting ducts. CONCLUSIONS: In conclusion, the present study shows that tubule-tubule contacts are inconsistent between the macula densa region and the distal nephron but that the tubule-afferent arteriole contact is consistent and close in superficial nephrons. This morphology is compatible with the existence of a feedback mechanism between the superficial distal nephron and the afferent arteriole, apart from the one located at the juxtaglomerular apparatus.

Animals↗
PubMed1990

Spinal analgesia with plain 0.5% bupivacaine administered at spinal interspace L2-3 or L4-5.

Forty patients (age range 60-79 yr) undergoing transurethral surgery were allocated randomly to receive 0.5% plain bupivacaine 4 ml at the L2-3 (n = 20) or L4-5 (n = 20) space. The solution was injected over 30 s with the patient in the sitting position. The patient was kept sitting for 2 min, then placed supine and, 5 min later, placed in the lithotomy position. No significant differences were found in onset time, extent and duration of analgesia or duration of motor block.

Aged↗
PubMed1989

[Clinical aspects of spinal anesthesia administered using 0.5% isobar bupivacaine (Maracine) at the L2/L3 or L4/L5 level].

The effect of employing different interspaces for lumbar puncture during spinal anaesthesia was evaluated in 40 patients receiving 4 ml of 0.5% plain bupivacaine at level L2/L3 or L4/L5. No differences were observed in onset, spread or duration of analgesia. Furthermore, we found that only 80% of the patients, independently of the interspace used, had a cephalad spread to T8 and conclude that spinal anaesthesia using plain bupivacaine is not ideal for supraumbilical surgery.

Aged↗
PubMed1988

Lithium-induced structural changes in the cortical distal nephron localized by computer-assisted three-dimensional reconstruction.

Lithium treatment is known to cause tubule dilation in distal nephron segments both in rat and in man. However, due to the heterogeneous cell composition of the distal nephron and the cellular changes following lithium treatment, it has been difficult to identify the structurally changed segments. In this study we have therefore applied computer-assisted reconstruction of cortical distal nephron segments. Tubule dilation was demonstrated in connecting and initial collecting tubules and in the first part of cortical collecting ducts (CCD) whereas it was absent from distal straight and distal convoluted tubules. Principal cells (P cells) in the CCD showed swelling of the cytoplasm, accumulation of actin-like microfilaments, and abnormal arrangements of basolateral membranes. Connecting tubule cells (CNT cells) showed similar but less pronounced changes. Intercalated cells (I cells) showed an accumulation of vesicles in the apical cytoplasm and a reduced luminal surface area. Lesions in P and CNT cells may, at least in part, explain the diabetes insipidus and sodium loss found during lithium treatment. Proton secretion in I cells is probably mediated by an ATPase present in the luminal membrane. The reduction in area of this membrane may explain why lithium-treated animals have a lowered ability to excrete an acid load.

Animals↗
PubMed1988

Ultrastructure of three-dimensionally localized distal nephron segments in superficial cortex of the rat kidney.

The ultrastructure of superficial distal nephron segments was analyzed after precise localization of tubule cross sections using computer-assisted three-dimensional reconstructions. Five systems of tubules, each with three interconnected distal tubules, were reconstructed and the lengths of the post macula densa segment of the distal straight tubule (DST), the distal convoluted tubule (DCT), the connecting tubule (CNT), and the initial collecting tubule (ICT) were determined. Each cortical collecting duct (CCD) was in continuity with only one tubule in contact with the renal capsule. In three of the five reconstructions, the two nonsubcapsular tubules fused and had a common connection to the subcapsular tubule. The length, between the macula densa (MD) and the confluence, of subcapsular tubules (2.68 +/- 0.15 mm) significantly exceeded the length of tubules not in contact with the renal capsule (2.05 +/- 0.10 mm). This difference was mainly due to a longer ICT in subcapsular tubules. Subcapsular tubules always contacted the renal capsule in the early DCT and often again in the ICT. Cells in the early DCT showed more microvilli on the luminal surface and more infoldings of basolateral membranes than cells in the late DCT. The ultrastructure of intercalated cells (I cells) varied within a range of different manifestations and the ultrastructural variation of I cells was similar in all the analyzed tubule segments. Connecting tubule cells and principal cells were similar in ultrastructure in all tubule segments and cortical levels analyzed.

Animals↗
PubMed1988

Erectile dysfunction in multiple sclerosis.

In a sample of 29 impotent men with multiple sclerosis and erectile problems, penile arterial inflow and venous outflow were within normal limits. In 26 patients, the pudendal evoked potential (PEP) was abnormal, and eight of these also had abnormal bulbocavernous reflex (BCR). Three patients had abnormal PEP and normal BCR, and of these, two had normal and one had abnormal nocturnal erectile activity. The validity of PEP/BCR testing was supported by normal findings in six patients with MS and without erectile problems. Nocturnal erectile activity was normal in 11 patients, of whom nine had abnormal PEP and/or BCR. A high disability score corresponded poorly with both reduced sexual function, insufficient nocturnal erectile activity, and abnormal PEP and/or BCR. Intracavernous injection of papaverine gave erection in 27 patients, the dose needed to create an erection being inversely related to the level of disablement. PEP and BCR testing may be more sensitive in defining neurogenic erectile dysfunction (ED) than nocturnal erectile activity. We considered 26 of the cases to have a neurogenic cause of ED and three to have mainly a psychogenic cause.

Adult↗
PubMedDate not supplied

Ultrastructure of distal nephron cells in rat renal cortex.

Distal nephron segments in the rat renal cortex contain distal convoluted tubule cells (DCT cells), connecting tubule cells (CNT cells), intercalated cells (I cells), and principal cells (P cells). The present study was carried out to expand present knowledge on the ultrastructure of these cells. The cells were sampled from superficial cortex and analyzed by electron microscopy. Several morphometric parameters were determined and statistical comparison between cell types was performed. Significant structural differences between the cell types were demonstrated. DCT cells showed the highest volume density of mitochondria whereas the amplification of basolateral membranes was higher in CNT cells than in I and P cells. The surface density of the membrane that bounds intermediate vesicles in the apical cytoplasm was twofold higher in I cells than in the other cell types. The morphological differentiation found in the present study adds to available evidence indicating a functional differentiation between the cell types and provides a reference for structure-function correlations in these cells.

Animals↗
PubMedDate not supplied

Structural adaptation of intercalated cells in rat renal cortex to acute metabolic acidosis and alkalosis.

The structural responses of cells in the distal convoluted, connecting, and collecting tubule to acute acid/base changes were investigated by electron microscopy. Acute metabolic acidosis was induced by administration of ammonium chloride, and acute metabolic alkalosis by potassium or sodium bicarbonate. Morphometric analyses were performed on micrographs of randomly selected distal nephron cells. No structural responses were found in distal convoluted tubule cells, connecting tubule cells, or principal cells but prominent changes were observed in intercalated cells (I cells). Thus, the surface density of the luminal membrane in I cells was significantly higher in acidotic animals and lower in KHCO3 alkalotic animals than in controls. On the contrary, the surface density of the membrane that bounds apical vesicles was higher in KHCO3 alkalotic and lower in acidotic animals than in controls. These results suggest that the luminal membrane is internalized during alkalosis and that the membrane that bounds apical vesicles is transferred to the luminal membrane during acidosis. Since a proton translocating ATPase may be present in the luminal membrane the observations are consistent with the possibility that cortical I cells participate in the maintenance of acid/base homeostasis.

Acidosis↗